1. Field of the Invention
The present invention relates to a recording apparatus, and more particularly, it relates to a recording apparatus having an encoder for detecting a position and a speed of a carriage on which a recording head is mounted.
2. Related Background Art
In so-called serial recording apparatuses wherein recording is effected by moving a carriage on which a recording head is mounted along a guide shaft, a magnetic linear encoder, an optical linear encoder or the like has been used to detect a position and a speed of the carriage.
In the recording apparatuses having the magnetic linear encoder, a magnetic scale portion is arranged in the apparatus, and a detection portion comprised of an MR element (ferromagnetic reluctance effect element) is arranged on the carriage shiftable relative to the scale portion. On the other hand, in the recording apparatuses having the optical linear encoder, a scale portion formed from a slit-shaped film is arranged in the apparatus, and a reading portion having a sensor of light-permeable type or light-reflection type is attached to the carriage shiftable relative to the scale portion.
In such recording apparatuses, in order to determine address of the scale of the (magnetic or optical) linear encoder, the following method has been adopted.
That is to say, a photo-interrupter is arranged in the apparatus independently from the linear encoder, so that all of the addresses on the entire area of the scale can be determined on the basis of a reference position of the scale where an optical axis of the photo-interrupter is blocked by a portion of the carriage. And, on the basis of the address of the scale determined by this method, a shift position of the carriage is determined and the recording is effected by the recording head mounted on the carriage at that shift position. Further, when the recording head is of ink jet type, a sucking operation or a capping operation is effected at a predetermined position on the basis of the address of the scale as ink discharge recovery treatment for the recording head.
By the way, in the above-mentioned conventional techniques, since the photo-interrupter is arranged in the apparatus independently from the linear encoder to determine the address of the scale of the linear encoder, in order to correctly or accurately determine the address of the scale, dimensional accuracy of parts of the photo-interrupter itself, attachment accuracy of the photo-interrupter to the apparatus and switching accuracy of signal output when the optical axis of the photo-interrupter is blocked by the portion of the carriage must be enhanced.
Further, in consideration of the ink jet recording apparatus wherein the sucking operation and the capping operation for the recording head are required, in order to perform positive sucking and capping operations, attachment accuracy of a recovery unit (for effecting the sucking and capping operations) with respect to the attachment position of the photo-interrupter must also be enhanced, as well as the above-mentioned accuracies.
Accordingly, if various dimensional errors are accumulated, sure capping operation and/or sucking operation cannot be performed.